1. Field of the Invention
The present invention relates to a liquid crystal display device and a display apparatus, particularly to a Fringe Field Switching (FFS) mode or In-Plane Switching (IPS) mode liquid crystal display device and a display apparatus having the same.
2. Description of the Related Art
In the FFS mode or IPS mode liquid crystal display device, pixel electrodes and a common electrode are provided on the same substrate side, in which a lateral electric field almost in parallel to the substrate surface is formed and the lateral electric field drives a liquid crystal device to display images. For example, in the FFS mode liquid crystal display device, such an example is described in which a common electrode is arranged in a plate form or comb tooth form on a substrate and pixel electrodes having a slit are arranged on the common electrode (for example, see Patent Reference 1 (JP-A-2001-42336) and Patent Reference 2 (JP-A-2002-229032)).
On the other hand, in recent years, for a liquid crystal display device for use in mobile appliances, a transreflective liquid crystal display device is disclosed in which the dark state and the visibility under ambient light are improved in the IPS mode (for example, see Patent Reference 3 (JP-A-2005-338256), Patent Reference 4 (JP-A-2005-338264), Patent Reference 5 (JP-T-2005-524115) and Patent Reference 6 (JP-A-2006-71977)). In these liquid crystal display devices, since no scattering film is provided in the reflective display area, the reflection efficiency of light from the ambient light is low, and the viewing angle is narrow in the reflective mode.
Then, in the transreflective liquid crystal display device, a FFS mode or IPS mode liquid crystal display device is considered that has a scattering film with projecting patterns on the front surface side in the reflective display area. A prior art FFS mode liquid crystal display device is described with reference to FIG. 11.
The liquid crystal display device shown in the drawing is a transreflective liquid crystal display device 1 having a transmissive display area X and a reflective display area Y in a single pixel. The liquid crystal display device 1 has a liquid crystal panel formed of a first substrate 10, a second substrate 20 that is provided on the device forming surface side of the first substrate 10 as facing thereto, and a liquid crystal layer 30 sandwiched between the first substrate 10 and the second substrate 20. In addition, in the liquid crystal panel, polarizers 40 and 50 are bonded to the outer surfaces of the first substrate 10 and the second substrate 20, and on the outer side of the polarizer 40 on the first substrate 10 side, a backlight (not shown) to be a light source for transmissive display is provided.
Among them, the first substrate 10 is formed of a transparent substrate such as a glass substrate, and a thin film transistor (TFT) 1 is provided on the surface facing the liquid crystal layer 30. On this surface, a common line 11 is extended in parallel to a gate line 2 configuring the TFT 1. They are covered with a first interlayer insulating film 13.
Then, on the first interlayer insulating film 13 in the reflective display area Y, a scattering film 14′ is provided that is formed of an insulating film and has projecting patterns 14a′ on the front surface side for scattering the light incident from the second substrate 20 side. The projecting patterns 14a′ are arranged randomly.
In addition, on the scattering film 14′ and the first interlayer insulating film 13, a common electrode 15′ is provided that is formed of a transparent electrode on the area except the top of the drain electrode 12b, and the common electrode 15′ is connected to the common line 11. Moreover, on the common electrode 15′ on the scattering film 14′ in the reflective display area Y, a reflective film 16′ is provided. Then, on the first interlayer insulating film 13, a second interlayer insulating film 17′ is provided as it covers the common electrode 15′ and the reflective film 16′. Here, the common electrode 15′, the reflective film 16′ and the second interlayer insulating film 17′ formed on the scattering film 14′ are formed to have projecting patterns as similar to the surface topology of the scattering film 14′.
On the second interlayer insulating film 17′, a pixel electrode 18′ is provided that has a plurality of slits 18a′ connected to the drain electrode 12b of the TFT 1. Then, an electric field is generated between the end parts of the electrode part arranged as the slit 18a′ is sandwiched and the common electrode 15′, whereby a lateral electric field almost in parallel to the substrate surface is applied to the liquid crystal layer 30.
On the other hand, the second substrate 20 is formed of a transparent substrate such as a glass substrate, and on the surface of the second substrate 20 facing the liquid crystal layer 30, R (red), G (green), and B (blue) color filters 21 and an alignment layer 22 are provided in this order. In addition, on the surface of the alignment layer 22 facing the liquid crystal layer 30 in the transmissive display area X, a non-phase difference layer 23 is provided, and on the surface of the alignment layer 22 facing the liquid crystal layer 30 in the reflective display area Y, a phase difference layer 24 and a flattened layer 25 are provided in this order. Then, on the surfaces of the non-phase difference layer 23 and the flattened layer 25 facing the liquid crystal layer 30, an alignment layer 26 is provided.